This invention relates to new and useful improvements in shirred synthetic sausage casings, and more particularly, to the closure of the end of a shirred sausage casing.
Casings, especially those prepared from collagen, are manufactured as hollow, thin-walled tubes of great length. For convenience in handling and in filling collagen casings are shirred from lengths of 60 feet or more down to a shirred and compressed length of several inches.
After tubular casings are shirred they are packaged and shipped, for example, to meat packaging houses where individual shirred strands are automatically fed onto stuffing horns and pressurized meat emulsion extruded into the casings to their fully extended lengths.
Heretofore, when food casings were stuffed manually the operator would simply deshirr a short length of casing from an end thereof and effect the closure preventing the meat emulsion extruding into the shirred casing from being lost from the open end. In the case of automated filling equipment the high speed of such operations dictates that the end closure or plug in the casing be formed during manufacture of the casing per se, rather than during filling operations.
The incidents of end-closure failure with preformed closures is not uncommon. High speed automated filling operations can lead to end-closure "blow-out" or unwinding of the closure due to impact occurring, for example, when the casing is fed onto the horn of a filling machine. The shock created by such impact increases the risk of end-closure failure. Similar problems can occur if the end-closure plug is not centered in the bore of the strand. When the filling horn on certain equipment indexes in a strand with the plug not centered it is likely to blow out the end of the strand when filling commences. Accordingly, there is a need for an improved method and apparatus for making end-closures on shirred tubular casings which will have a lower incidence of failure when used in conjunction with high speed automated filling equipment.
The present invention provides for a more dependable end-closure on shirred tubular food casings and means for so accomplishing. The improved method of the present invention provides for positioning the end closing plug completely inside the bore of the shirred strand, rather than extending to the terminal end of the strand. By recessing the plug within the bore of the strand followed by conical shaped inverted casing at the terminus of the strand a cushioning or shock absorbing affect is created reducing the incidents of end-closure failure during filling operations. The conical shaped arbor or nose section of the improved end-closure apparatus provides the means for centering the tip of the end-closure plug in the bore of the casing strand.
In addition to the foregoing, the end-closure method of the present invention utilizes up to 50% less casing material in affecting a strand closure than previous methods. Because the end closure is self regulating the length of casing in the closure is constant and not sensitive to the number of turns of the arbor.
Thus, it is one principal object of the present invention to provide a new and improved method of closing the fore-end of a shirred strand of food casing.
It is a further object of the present invention to provide an improved apparatus for making centered and recessed end-closures on food casings that have a lower incidence of failure during filling operations.
A still further object of the present invention is to provide an improved end-closure on a shirred food casing which has built-in shock absorbing properties positive enough not to blow out at the start of the filling process.
These and other objects, features and advantages of the present invention will become more apparent from the following more detailed description.